Sigma makes numerous lenses,
but the "all-purpose" zooms have been the best selling models
in their vast line. Replacing the "DL Hyper Zoom" models,
the new 28-200mm and 28-300mm lenses are designated as "Compact
Hyper Zoom Macro." This suggests a significant downsizing and
the new lenses are certainly smaller and lighter than their predecessors.
As a bonus they offer two other advantages: closer focusing and a superior
optical formula that improves overall image quality.

In order to give these Sigma zooms a good workout, I shot hundreds of
images during several vacation trips. Subjects included the colorful
performers at a Native American powwow, family and friends enjoying
cottage life, the competitors at the World Jousting Competition, and
high-powered motorcycles tearing around a winding road. In the majority
of situations, these all-purpose zooms proved to be competent performers.
They worked perfectly on a Canon EOS-3 and digital D60; all of the cameras'
high tech features were maintained.

In spite of the numerous lens elements, flare is well controlled
in both Sigma zooms. (The 28-300mm zoom at 300mm setting;
EOS D60 at ISO 200.)

Lens Features
Except for size, the two Compact Hyper Zooms are almost identical. Both
are nicely finished in matte black with white numerals that are very legible
though a bit small. As with most zoom lenses, there's no depth of
field scale. The lens mount is made of metal. The zoom ring is very wide
(1.5"), well ribbed, and rubberized. Though narrower (0.75"),
the ribbed focus ring is adequately wide. Both zoom and focus mechanisms
operate smoothly; manual focus has enough friction for a familiar feel,
especially in the 28-300mm zoom. A rotation of a mere 30Þ changes
focus from "macro" to infinity allowing for fast focusing.
An internal focus mechanism also helps assure quick autofocus. As a bonus,
the front element does not rotate; this feature is useful especially with
a polarizer because the filter's effect does not change when focusing.

Both models are certainly light in weight and as small as some 28-105mm
or 28-135mm zooms. When shifting from 28mm to longer focal lengths, the
internal telescoping barrel extends, by 2" with the 28-200mm model
and by 3" with the 28-300mm model. The internal barrel includes
data on macro magnification ratios for several focal lengths, for use
in extremely close focusing. There's a switch for locking the zoom
ring at the 28mm position, so the internal barrel does not protrude when
the lens is carried pointing downward. Frankly, this is not necessary
since the zoom action is adequately stiff.

Flare is very well controlled and the corner-cut lens hood shades the
front element at all focal lengths. In extreme sidelighting, at a mid-morning
jousting competition, I occasionally needed to change my shooting position
slightly when flare was noticeable on the viewing screen.

Even at 300mm, the Sigma 28-300mm zoom produced high image
quality, especially at f/8 or f/11. As with all zooms with
a maximum aperture of f/6.3 at the longest focal lengths,
autofocus was not always lightning fast but remained quite
reliable. (At f/8; EOS-3; Hoya polarizer; Kodak Elite Chrome
100.)

28-200mm Compact Hyper Zoom
This shorter zoom is particularly compact, so it's very portable.
In spite of a 5 oz reduction in weight since the previous DL model, optical
quality has been maintained. Two aspherical elements in the optical formula
control distortion and enhance sharpness at the edges of the image.

The minimum focusing distance is about an inch shorter, useful for occasional
nature close-up shots. Naturally, Sigma's true macro lenses produce
much higher magnification and even better image quality. For the optimum
results in close focusing, I stopped down to f/16. This small aperture
also provided adequate depth of field to keep an entire subject within
the range of acceptable sharpness. To prevent blur from camera shake,
I used a tripod, but on sunny days with an ISO 400 film, a tripod may
not be required.

Evaluation
At greater focusing distances, image sharpness was very high across the
frame at all apertures in the 28-135mm range. There was no need to stop
down from maximum aperture to increase image quality. This consistency
at all f/stops is a sign of a well-designed optical formula. At longer
focal lengths, center sharpness was high; stopping down to f/8 was useful
for increased edge sharpness. Contrast was moderately high at all focal
lengths; images that I made on a hazy day at the powwow would benefit
from some contrast adjustment in Photoshop.

As suggested by the "Macro" designation, the
Sigma zooms have close focusing capability. True macro lenses
can produce much higher magnification, but these zooms are
useful for moderate close-ups of flowers or other small
subjects. (The 28-300mm zoom at 120mm; f/11; EOS D60 at
ISO 200.)

As with most all-purpose zooms,
I found noticeable barrel distortion (bowing outward of lines near the
edge of the frame) at short focal lengths. At long zoom settings, pincushion
distortion (bowing inward of lines) was noticeable. Frankly, this would
be relevant only in formal architectural photography, not a typical use
for a lens of this type. I noticed some light falloff (slight darkening
of the corners of my slides) at wide apertures, when a polarized sky filled
the frame. This is also common with wide range zooms. With this model,
it may be caused by the narrower diameter of the front element. However,
I applaud the designers for the smaller size because the lens accepts
62mm filters, instead of the more expensive 72mm size like its predecessor.

Autofocus Evaluation
With the EOS-3 and EOS D60, autofocus was reliable with fairly quick response
and the usual high-pitched hum. In Continuous AF, the camera/lens combination
had no difficulty in tracking moving Caribbean dancers and cars traveling
at 30 mph. With motorcycles tearing along at higher speeds, the first
frame or two of a series was not always sharp; still, some of the subsequent
frames exhibit razor-sharp focus. Photographers who frequently shoot action
subjects will prefer one of the (large, heavy, expensive) Sigma HSM lenses
with ultrasonic focus motor and wider maximum aperture.

Mount either of the Sigma zooms on a compact SLR camera
with built-in flash, and you have a small but versatile
photographic system. Whenever it's inconvenient or
impractical to carry a lot of gear, this combination can
be a suitable alternative. (The 28-200mm zoom at 80mm; f/8;
Hoya polarizer; EOS D60 at ISO 100.)

The Bottom Line
Since this 28-200mm Sigma model provides very good image quality and reliable
autofocus, it would be a great choice for family and travel photography.
My findings confirm Sigma's claims that the new Compact Hyper Zoom
model provides higher image quality than the previous DL Hyper Zoom. For
the absolutely highest image quality, shoot in the 28-135mm range. The
resulting negatives or digital images should be suitable for making an
excellent 8x10" print, the largest that most families want. At longer
focal lengths, image quality is adequately high for an excellent 5x7"
print or a good 8x10" glossy, particularly at f/8-f/16.

28-300mm Compact Hyper Zoom
This longer zoom is certainly larger and heavier, but it's a half-inch
shorter and an ounce lighter than the previous DL model. Although the
diameter is identical, the new Compact Hyper Zoom accepts 67mm filters
instead of the larger 72mm size. (That's possible because the internal
barrel is narrower.) For a zoom with such a wide range of focal lengths,
it still falls into the compact category.

Because this 28-300mm extends to long focal lengths, it includes two types
of special elements. This is important because the inherent optical flaws
are quite different at 28mm and 300mm; both have been addressed in this
lens. Two aspherical elements are used to correct "spherical aberration
and coma" at short focal lengths, while an element of SLD (Super
Low Dispersion) glass helps to correct "chromatic aberration"
at long focal lengths. Instead of a long discussion about aberrations,
I'll just say that the special elements should ensure higher edge-to-edge
sharpness and help to reduce distortion.

Autofocus Evaluation
At the longest focal lengths, the maximum aperture is quite small (f/6.3).
Many autofocus SLR cameras disengage autofocus when the effective maximum
aperture is smaller than f/5.6. However, autofocus should continue to
operate with most AF cameras, when using this Sigma model at any focal
length. Thanks to an internal device in the lens, the maximum aperture
information transmitted to the camera is never smaller than f/5.6. Even
so, exposures remain accurate with through the lens light metering.
Because an f/6.3 aperture does not transmit much light to a camera's
AF sensors, autofocus was a bit slow at long focal lengths, especially
in low light or when using a polarizer. I have experienced the same problem
with all f/5.6-6.3 zoom lenses. This is one of the tradeoffs for modest
size and weight.

Evaluation
In terms of optical performance, this 28-300mm Sigma zoom is similar to
the 28-200mm model. Images made at the widest aperture in the 28-170mm
range are impressive. Again, there's no need to stop down from the
maximum aperture, because image quality is quite consistent at all f/stops.
The difference between the two lenses is most noticeable at the 170-200mm
settings: the 28-300mm zoom produces higher sharpness across the frame
at the maximum aperture.

Performance in the 200-250mm range is good at f/5.6; central sharpness
is high, adequate for a fine 8x10" print. This is important because
most people tend to center the subject in typical family and travel pictures.
For the best edge-to-edge sharpness at any focal length from 200-300mm,
it's worth stopping down to f/8 to prevent softness at the edges
of the frame.

Shooting at a small f/8 aperture can cause a problem at long focal lengths,
especially when using a polarizing filter. With ISO 100 film, the shutter
speeds are rarely high enough to prevent blur from camera shake. For the
best results when hand holding the camera, use an ISO 400 film--or
the ISO 400 equivalent in a digital camera--for higher shutter speeds.

Unlike the previous 28-300mm DL Hyper Zoom, the new model offers very
close focusing at all focal lengths. This can be used to fill the frame
with a large blossom or for tight headshots of small subjects such as
cats. I was quite satisfied with the high image quality--especially
in the f/11-f/22 range typically required to maximize the range of sharp
focus.

The Bottom Line
Although the 28-200mm Compact Hyper Zoom would meet most needs, some folks
will prefer this 28-300mm model. The ability to select longer focal lengths
can be useful for distant subjects: youngsters participating in sports
events, for example. In the 28-200mm range, its optical performance is
even better, useful for those who often make, or order, 8x10" prints.

Final Assessment
As with any brand, the premium-grade zooms--such as Sigma's
APO EX series--produce the most impressive image quality. However,
such lenses are hefty, large, and far more expensive, so they're
less practical for family and travel photography. As well, they rarely
cover all of the most popular focal lengths, so that means buying--and
carrying--extra lenses. Understandably, there's a much higher
demand for all-purpose zooms and the Sigma models will meet the expectations
of most consumers.

Are you a photo enthusiast who already owns a full system? If so, you
may still want to buy a 28-200mm or 28-300mm zoom for use with a compact
SLR camera with built-in flash. This combination may be all you would
need while hiking, cycling, skiing, or simply walking for hours on sightseeing
trips. Considering their many features, modest price, and satisfying image
quality, either of the Sigma models would be a great choice.